


My Biggest Sin

by Winmance



Series: Tumblr Prompt [11]
Category: Supernatural
Genre: Age Difference, Bottom Dean, First Time, M/M, Older Sam, Soulless Sam Winchester, Time Travel, Top Sam, Virgin Dean
Language: English
Status: Completed
Published: 2018-04-27
Updated: 2018-04-27
Packaged: 2019-04-28 17:48:45
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,559
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14454564
Author URL: https://archiveofourown.org/users/Winmance/pseuds/Winmance
Summary: He was at the bar, drinking his beer alone, when he saw him. He’s tall, so freaking tall, with the biggest shoulders he ever seen, two long, long legs that seemed to never end. But most of all, he looked like Sammy. His Sam, his baby brother, the light of his life, his biggest sin.





	My Biggest Sin

**Author's Note:**

> Beta by @debivc78

"Have you ever done this?" Sam asks, taking his belt off

"Yeah, of course” Dean laughs, shifting uncomfortably on the bed.

Sam smirks, throwing his shirt aside before moving to the bed slowly. Dean swallows hard, not sure of what he’s supposed to do.

“What about the truth?” Sam whispers in his ear, biting his lobe.

“I… No”

“No what?”

“No, I never done this” Dean closes his eyes, falling back on the bed. He's never done this, never even thought about this.

He was at the bar, drinking his beer alone, when he saw him. He’s tall, so freaking tall, with the biggest shoulders he ever seen, two long, long legs that seemed to never end. But most of all, he looked like Sammy. His Sam, his baby brother, the light of his life, his biggest sin. He started seeing him differently a few months back, and now, all he can think about is how soft Sam’s lips may be, how cute he is when he blushes, and Dean wants to throw up every time he thinks of it.

So, seeing this man- it was too much temptation.

“How old are you, Dean?”

“18”

“If you don’t stop lying, I’ll have to spank you, you know” Sam bites his neck, making Dean moan in pain-pleasure

“16” He swallows hard again; his hard dick painfully trapped in his jeans “You?”

“26”

“Really? You seem… Older”

“Yeah, I guess I am, in some ways” Sam slides his hands under Dean’s shirt before taking it off. He moves his mouth until he's able to lick Dean’s right nipple, while his other hand starts touching his dick through his clothes.

“Fuck” Dean moans, his fingers clenching in Sam’s hair “Don’t stop”

“Wasn’t plannin on it."

Dean never thought that someone sucking on his nipples would feel so good, but yet, here he is, so close to coming from nothing else but Sam’s mouth on his hard nipples.

“Ready for more, sweetie?” Sam asks, shoving Dean’s pants off

“I… Yeah”

“Ask me nicely”

Sam pushes a lubed finger inside of him, making him close his eyes with pleasure. He'd only touched himself there once or twice, and it wasn’t near as good as it is now.

“Please”

“Ask me correctly”

“Please, fuck me” Dean moans, bouncing on the two fingers in his ass

“Say my name” Sam whispers, his fingers scissoring Dean

“No”

“Come on, Dean, if you don’t say it, I won’t do it”

“I… Please, fuck me, Sam”

He can’t help but shiver when the name leaves his lips. When the man asked him what he wanted to call him, Dean had said the first thing that came to his mind. He doesn’t know what's more wrong. The fact that he called a perfect stranger by his brother's name, or the fact that the stranger doesn’t mind even a little.

There’s something cold, in the man, as if he's unable to express any feelings. He’s here, but his eyes are cold as if he's far away.

He wonders what his dad would think of the man, if he would think he’s a monster, or a freak. But then again, maybe Dean is a freak himself.

“Good boy” Sam says, rolling the condom on his dick.

Sam’s dick is… Well, it’s impressive, that the least that can be said. It’s long and big, and Dean isn’t sure he can take it, not sure anyone can take it, really.

“I won’t hurt you”

“Yeah? I’m not sure.” Dean laughs awkwardly, still staring at Sam’s hard dick

“Look at me” Sam orders, and for a moment, he looks so much like John that it scares the hell out of Dean. “I won’t hurt you. Ever, Dean. You mean too much to me”

“We met like, one hour ago” He frowns, pushing Sam slowly away from him. He’s feeling so small and vulnerable, naked on this big bed with a man who could probably throw him around with his little finger.

“Isn’t what he would say?”

“Who?” Dean asks, wondering if he can be fast enough to take his gun out of his bag without being caught by the man.

“Sam. Wouldn’t he say that?”

“I… Yeah, probably”

“You’re too tense, Dean”

Sam puts his hand on his chest, making him fall on the bed slowly.

“I’ll make it good” He whispers, kissing Dean’s lips slowly.

He starts kissing his neck, then his chest, licking and biting around his bellybutton, before lifting Dean's legs, now facing Dean’s hole.

He gave one small lick to his hard dick, sucking on the head before moving to his balls. He positions himself at his entrance, his hard breath hitting him, and Dean isn’t really sure how he feels about having someone's tongue here but when Sam starts licking him, he has no doubts about it.

“Shit” He moans, throwing his head back.

He puts his feet on Sam’s shoulders, urging him to go harder, deeper, and Sam obliges with a smile. Dean slides his fingers in Sam’s hair, dragging him closer and all but fucking his face with his ass.

“Gonna… Gonna come, stop”

Sam smiles, giving one last lick before moving up, until he’s able to kiss Dean.

The kiss is rougher than before, Sam taking control over it, fucking Dean’s mouth with his tongue. It’s so good and so intense that Dean doesn’t even notice that Sam’s lubed dick is resting against his entrance, his legs around his shoulders.

“Deep breath” Sam orders

Dean has no time to think about what it means because next thing he knows, Sam's monster dick is pushing inside of him, and Dean closes his eyes to the pain and the pleasure that follows.

It’s weird to have someone inside of him, but Sam is gentle, taking his time and making sure that Dean is ok before finally pushing all the way in.

“It’s… Fuck, is it in? Like, completely?” Dean is already panting

“See for yourself”

Sam takes one of Dean’s hand and puts it against his hole, and Dean can feel it, can feel how tense and wide open his hole is, how Sam’s balls are resting against him. He pinches the head of his dick to prevent himself from coming, making Sam smile proudly.

“Can I move?”

Dean nods, and that’s all it takes for Sam to start. It’s slow at first, giving Dean timt to adjust, but once he sees that Dean is enjoying it, he finally lets go.

He moves faster, going in and out as fast as he can, before moving so he’s in a sitting position, Dean’s legs still around his shoulders.

“Fuck, Sam!” Dean screams when Sam finally hits his prostate “Again, do it again”

Sam smirks, positioning himself until he’s sure he’ll hit against Dean's prostate with each trust.

He starts spanking Dean’s ass, making the younger boy clenching around him. He can already imagine how Dean will look, with red hand prints on his perfect little ass.

“Tell me how good it is” Sam says, pulling all the way out of Dean before making him roll on his stomach. Dean doesn’t even notice what is happening, too far gone to care, as Sam slides in with one movement.

“Fuck, fuck, fuck” Dean groans, his ass up while he tries to meet Sam’s moves

“Tell me” Sam giving him one hard trust, making Dean scream in pleasure

“Good, Sam, it’s good. So, freaking good. Feel so full”

“What a good little slut you make” He laughs, his hands so tight around Dean’s waist that he’ll surely leave bruises – He hopes he does. “Some things never change”

“W-What?”

“Hush, darling” Sam says, pushing Dean's head against the pillow “You’re so tight”

He fucks into Dean again and again, until he sees Dean searching for his dick and starting to jerk himself off. He goes faster, Dean legs spread wide.

“C-Coming, I’m- Fuck” Dean screams again, coming all over himself

He’s clenching so hard that Sam follows quickly, fucking Dean through his orgasm.

He collapses on top of him, both of them panting hard.

“Fuck” Dean moans, taking Sam’s hand in his “That was awesome”

“Yeah, I think so too” Sam kisses Dean cheek before slowly pulling out, throwing the condom away and getting up. “You should get going, shouldn’t you?”

“I… Yeah, I guess” The disappointment is palpable on Dean’s face, and Sam knows that he would have felt bad if he was still the old-Sam.

He looks so much like his own Dean, with his green eyes and his freckles everywhere. He remembers being 13 and wondering if Dean will ever look at him like he looks at Dean. Here he is now, looking at his brother's naked body, their sweat mixing on him and his virginity now gone.

“You can stay a little longer. But I need to get going before tomorrow”

“I don’t… I mean, I should go”

Sam smiles, climbing on the bed again.

“Don’t act like that, Dean. We can have more fun, if you want”

Dean bits his lips, looking down for a moment.

“Yes, I would love to”

One more night, and then Sam will need to go back at his own time, with his own Dean who can’t even look at him anymore. Now, though, he still has a few more hours with his brother.


End file.
